11981633418 has 24 divisors (see below), whose sum is σ = 26227840548. Its totient is φ = 3952703232.

The previous prime is 11981633413. The next prime is 11981633429. The reversal of 11981633418 is 81433618911.

11981633418 is a `hidden beast` number, since 1 + 1 + 9 + 8 + 1 + 633 + 4 + 1 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 11432527929 + 549105489 = 106923^2 + 23433^2 .

It is a super-3 number, since 3×11981633418³ (a number of 31 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (11981633413) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3429421 + ... + 3432912.

Almost surely, 2^11981633418 is an apocalyptic number.

11981633418 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

11981633418 is an abundant number, since it is smaller than the sum of its proper divisors (14246207130).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

11981633418 is a wasteful number, since it uses less digits than its factorization.

11981633418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6862438 (or 6862435 counting only the distinct ones).

The product of its digits is 124416, while the sum is 45.

The spelling of 11981633418 in words is "eleven billion, nine hundred eighty-one million, six hundred thirty-three thousand, four hundred eighteen".